Disaster Management can be defined as the organization and management of resources and responsibilities for dealing with all humanitarian aspects of emergencies, in particular preparedness, response and recovery in order to lessen the impact of disasters.
Urban flooding is a major problem in many parts of the world and is one of the most natural disastrous event which takes place every year, especially in the coastal cities. Urban flood, being a natural disaster, cannot be avoided; however, the losses occurring due to flooding can be prevented by proper flood mitigation planning. As such, it is necessary to have a proper estimation of flood extent and flood hazard for the different flow conditions so that proper flood evacuation and disaster management plan can be prepared in advance. The coastal urban flooding is a complex phenomenon which may occur in various forms such as: urban flooding due to high intensity rainfall; due to inadequate drainage and flooding caused by overtopping in the channels or rivers; flooding due to high tides, etc.
In coastal urban cities like Mumbai, mostly severe flood scenarios take place due to combination of surface flooding, channel overtopping, and tidal flooding. For effective coastal urban flood management and mitigation plans, the possible flooding scenario is to be simulated for extreme rainfall events, or various return periods of rainfall and other design scenarios. This chapter discussed the integrated approach of coastal urban flood simulation using computer models, GIS, and remotely sensed data. Various urban flood models available are discussed briefly. Two of the urban flood models, viz. IFAM and HEC-HMS-RAS, are discussed in detail and their applications are illustrated through two case studies.